This is a Butterfly Orchid (sorry, there are a lot of orchids, I can't find a link I trust) are- easily identified by the onion shaped bulb. David said the spores (seeds? I can't remember) have to land in a craggy spot on the bark of a tree - white mangrove in this case - and when it gets attacked by a fungus, it turns around and eats off the fungus instead of dying. Pretty cool.